The present invention relates to an optical disk and a recording/reproduction apparatus which uses this optical disk. Particularly, the invention relates to the structure of an optical disk having in its partial area a memory provided separately from the recording medium of the disk, and to a recording/reproduction apparatus which uses this optical disk.
A variety of electronic systems using recording mediums of optical disks which are easy for large-scale production and reliable in operation have been developed and put on the market recently. These optical disks are represented, for example, by the compact disk (CD) used for storing music, the digital video disk (DVD) used for storing pictures inclusive of the movies, and the CD-ROM and DVD-ROM used for storing computer application programs, game programs and various information.
Optical disks for the CD, CD-ROM and DVD-ROM are made of plastics, which enables the low-cost large-scale production of disks, with information being pre-recorded thereon. These reproduction-only disks, however, do not allow the additional data recording, and therefore it is not possible to record the result of process of data which has been read out of the disk or record the number of times of reproducing operation of the disk, for example. Therefore, it is unstable to be used for a information management system or the like with the capability of storing the results of games, restricting the access to computer application programs or limiting the number of times of playback of audio/video records.
Although there is known an optical disk which allows the additional data recording, it is expensive due to the complex fabricating process and does not enable the low-cost large-scale production. Moreover, it is necessary to pre-record the main information on each disk individually, and record additional data with a high-power optical recording head, resulting in an expensive recording/reproduction apparatus as compared with the simple reproduction apparatus.
There is known a scheme of recording control information on a medium which is provided separately from the medium of the main information. Specifically, a magnetic tape cartridge has the attachment of a semiconductor memory used for the management of the main information on the magnetic tape. The semiconductor memory is accessed for data input/output in a direct contact manner. Although this scheme may be applied also to the optical disk, it imposes the difficulty of data transmission to/from the semiconductor memory which is turning together with the disk.
An object of the present invention is to provide a reproduction-only optical disk which is intended for the CD, CD-ROM, DVD-ROM, etc., made of plastics for the low-cost, large-scale and high-yield manufacturing and pre-recording, and provided in its partial area with a memory which writes and reads out simply and reliably additional control information for the management of the main information on the disk so that the disk is useful for a information management system or the like which offers game programs, computer application programs or audio/video records with the capability of storing the results of games, restricting the access to computer application programs or limiting the number of times of playback of audio/video records, for example, and also to provide an inexpensive recording/reproduction apparatus which uses this optical disk.
In order to achieve the above objective, the inventive optical disk and recording/reproduction apparatus includes inside the disk a memory, which is built in the form of a semiconductor IC chip for example, used for the management of the main information of a game program, computer application program or audio/video record, in addition to the recording medium which stores the main information.
The memory incorporates a signal processor for transforming the control information into recording data for storing, a memory for storing the control information, and a controller for controlling the writing and read-out of the memory and treating the main information based on the analysis of control information, e.g., the number of times of reproduction of the main information or the restriction of reproduction of the main information.
For receiving power in the form of a signal to be supplied to the circuitries of semiconductor IC chip, an electromagnetic coupling means, i.e., a receiver means, such as an antenna is built in or disposed beside the IC chip. Alternatively, it is disposed in an annular or one or multi-turn spiral form on the disk.
The IC chip further incorporates a rectifier for converting the signal received by the receiver means into power. Similarly, for the communication of control information between the optical disk and the recording/reproduction apparatus, another electromagnetic coupling means, i.e., a transmitter-receiver means, such as an antenna is built in or disposed beside the IC chip. Alternatively, it is disposed in an annular or one or multi-turn spiral form on the disk.
The signals sent to the electromagnetic coupling means for control information transfer and power supply have their transmission band set outside of the main information recording band or the reproduction band in the case of the multiple-speed playback of the main information so that the signals do not affect the recording and reproduction of the main information. Accordingly, one of the following two kinds of means are required depending on the band of the signals transmitted to the electromagnetic coupling means for control information transfer and power supply.
(1) In the case of setting a lower transmission band, it is necessary for the electromagnetic coupling means to have a larger inductance in order to raise the coupling coefficient (transmission efficiency) for coping with the lower frequency. For the achievement of this inductance, at least the electromagnetic coupling means for control information transfer and power supply among the devices associated with the memory are located at positions outer than the outer bound of the recording medium on the disk, and they are disposed in an annular or one or multi-turn spiral form on the disk. For ensuring a large inductance of the electromagnetic coupling means, they are each formed of a conductor coil and a soft magnetic core. However, this arrangement is disadvantageous in regard to the recording capacity of the disk due to the disposition of the memory in the disk outer section which could provide a large recording area.
(2) In the case of setting a higher transmission band, it is possible for the electromagnetic coupling means to have a sufficiently large coupling coefficient (transmission efficiency) without the need of a large inductance in dealing with the higher frequency. It is even desirable to lower the electromagnetic coupling in order to minimize the influence of stray capacitance. In this case, the memory has its shape and location determined with respect to the following affairs.
(2-1) The memory is provided by being built therein or disposed thereby with electromagnetic coupling means. At least the electromagnetic coupling means for control information transfer and power supply among the devices associated with the memory are located at positions within the range of radius on the disk where the recording medium is formed and on the side of the disk opposite to the side on which recording and reproduction take place between the recording medium and the disk medium record/reproduce circuit of the recording/reproduction apparatus.
Based on this arrangement, the recording medium which is generally formed of a metallic film works as a reflector for the electromagnetic coupling means, which thus transmit the signals efficiently. This arrangement is applicable obviously only to the case where, at least, the main information is recorded and reproduced only on one side of the disk.
(2-2) At least the electromagnetic coupling means for control information transfer and power supply among the devices associated with the memory are located at positions inner than the inner bound of the recording medium on the disk, and they are built in or disposed beside the memory. Alternatively, the electromagnetic coupling means are disposed in an annular or one-turn spiral form at positions inner than the inner bound of the recording area of the recording medium on the disk. This arrangement is effective for the case where the disk has a multi-layer recording medium and recording and reproduction of the main information take place on both sides of the disk, for example. This arrangement is advantageous in regard to the recording capacity of the disk due to the disposition of the memory in the disk inner section which could provide a smaller recording area.
In case the transmitted signal for power supply and the transmitted signal for control information transfer do not interfere with each other, these signals are mixed, and the receiver for power supply and the transmitter-receiver for control information transfer as the electromagnetic coupling means are integrated to be a common device, which treats the mixed signal.
In the case of the inner disposition of the memory on the disk, while the disk is mounted on a disc-shaped turntable for high-speed recording and reproduction, the electromagnetic coupling means for control information transfer and power supply among the devices associated with the memory are located at least partially at positions outer than the clamping area of the disk on the turntable or outer than the mounting face of the turntable so that the transmitter-receiver and receiver as the electromagnetic coupling means are not precluded for their signal transaction by the turntable.
For balancing with the additional weight of the memory attached to the disk, a counterweight is put to the disk at the symmetrical position against the position of memory with respect to the center of rotation.
With the disk being mounted on the turntable of the recording/reproduction apparatus for high-speed recording and reproduction, the transmitter-receiver of the recording/reproduction apparatus for control information transaction with the memory on the disk and the transmitter for power supply to the memory are located at positions with distances virtually equal to the distances from the disk rotation center to the transmitter-receiver of the memory for data transaction and to the receiver for non-contact power supply from the outside, respectively.
In this case, the transmitter-receiver of the recording/reproduction apparatus for control information transaction with the memory on the disk and the transmitter for power supply to the memory have their shapes and locations determined with respect to the following affairs.
(1) In case the transmitter-receiver and receiver as the electromagnetic coupling means attached to the disk are disposed in an arcuate, annular or spiral form, the transmitter-receiver and transmitter as the electromagnetic coupling means of the recording/reproduction apparatus are disposed also in an arcuate, annular or spiral form on virtually concentric circles, or these devices are built in the form of a transmitter-receiver module disposed at a position which is away from the disk rotation center. The transmitter-receiver module has an integrated circuit arrangement inclusive of the transmitter-receiver and transmitter as the electromagnetic coupling means of the recording/reproduction apparatus and the associated driving circuitries.
(2) In case the transmitter-receiver and receiver as the electromagnetic coupling means on the disk are built in or disposed beside the IC chip, the transmitter-receiver and transmitter as the electromagnetic coupling means of the recording/reproduction apparatus are disposed in an arcuate, annular or spiral form on virtually concentric circles. Alternatively, the transmitter for supplying power to the memory is built in the form of a transmitter-receiver module and disposed at a position which is virtually on the center axis of the turntable.
The optical disk is generally formed of two pieces of plastic sheets stuck together, and the IC chip for the memory, with the electromagnetic coupling means being attached thereto, is disposed in regard to the disk thickness direction based on the following schemes.
(1) The IC chip for the memory and the electromagnetic coupling means are formed based on the insert-lamination scheme in the plastic sheet that is different from the plastic sheet for the formation of the recording medium. The plastic sheet, with the memory being insert-laminated, will have an offset by the thickness of the IC chip and electromagnetic coupling means, and therefore it is unstable for the formation of a recording medium on it.
(2) A recessed section is formed in one plastic sheet on its sticking side, the IC chip and electromagnetic coupling means are put in the recessed section, and both sheets are stuck. The IC chip and electromagnetic coupling means are concealed within the thickness of the stuck plastic sheets, and the disk surface does not swell. Moreover, another recording medium can be formed on the plastic sheet having the IC chip in the recessed section.
(3) The IC chip and electromagnetic coupling means are put in a recessed section which is formed on the side of plastic sheet opposite to the sticking side, and these members are glued with resin. This scheme enables the attachment of IC chips after optical disks have been completed, allowing the disk manufacturer to produce optical disks in the conventional manner and the distributer to put IC chips on afterward thereby to finish optical disks with the management function.
The IC chip can possibly fail in operation when it is exposed to a strong light, and therefore it is covered with light-blocking resin against the laser beam or the like used by the optical head.
The controller built in the IC chip is designed, for example, to focus the optical head of the recording/reproduction apparatus to a certain position so that it operates on the tracking control actuator to alter the electrical offset value of the focus system, for example, independently of the recording/reproduction apparatus. In consequence, it becomes possible in the future, when multi-layer optical disks having various recording capacities will be put on the market, for the memory on the disk to deal with the number of recording layers and recording positions across the layers thereby to control independently the focal position of the optical head for the reproduction of records, for example.